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J. P. BIRCH. 5 ROTARY STEAM ENGINE.

No. 63,694. Patented Apr. 9, 1867..

I f a 2 Z i 25 Z y L) I 1' f 2 gotten gttttw iilattmt @fficr JOHN P. BIRCH. OF PHILADELPHIA, IENNSYLVANIA, ASSIGNOR TO HIM- SELF AND W. PATTERSON, OF N EWBURYPORT, MASSACHUSETTS.

Letters Patent No. 63,694, dated April 9, 1867.

IMPROVEMENT IN ROTARY STEAM ENGINES.

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TO WHOM IT MAY CONCERN:

Be it known that I, JOHN P. BIRCH, of Philadelphia, in the county of Philadelphia, and State of Pennsylvania, have invented-certain new and useful improvements in Rotary Steam Engines; and I hereb declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, in Which- Figure 1 represents a longitudinal vertical sect-ion ofa steam cylinder with my improvements applied; and

Figure 2' is a transverse vertical section of the same, on the line :I: :c, fig. 1.

My invention relates to rotary engines in which the piston case or drum is mounted or has its hearing in and eccentrically to the steam cylinder. In engines of this class, the shaftof the piston ease'is usually -mounted cccen trically in one of the ends of the steam cylinder, and the pistons, placed in mortises formed in the drum, are pivoted to a pin secured in the centre of the other end of the cylinder; the pistons being in fact radii and revolving upon the axis of the steam cylinder. My invention more especially relates to the arrangement of these pistons, and it principally consists in combining them with the cylinder and hollow-piston drum in such manner that, although they actuate the drum and revolve upon the axis of the cylinder, they shall be unconnected with and independent of each other, and unattached to either the drum, or cylinder, or centre rod around which they revolve. Under this arrangement they are perfectly free to adjust themselves within the cylinder, and at the same time they may be removed therefrom with the greatest facility. My invention further consists in the use of prismatiepicces placed in the edges of the pistons, so as to increase the surface which bears against the cylinder, and upon which the steam acts. And also in the employment of a disk or plate pressed or held up against the end of the piston drum by means of springs, so that the steam cannot pass by or bear upon the end of the piston case of pistons which it contains. It also consists in the method of supporting or suspending the cylinder, as will be hereinafter described.

To enable those skilled in the art to make and use my invention, I will now proceed to describe the manner in which the same is or may be carried into effect by reference to the accompanying drawings.

Theshaft a of the piston-drum A has its bearing eccentrically in the head of the steam cylinder B. The axis of the drum and its shaft is represented by the line m m, and the axis of the cylinder by the line 12. 22. The piston case, as shown in fig. 2, is hollow, and has formed in it four mortiscs forv the reception of the pistons. The pistons 25 are placed in the mortises so that they shall radiate from a common centre, 2'. 0., the axis of the steam cylinder; and thus, although they are held in the piston case and cause its revolution, their axis of motion is eccentric to that of the case. Although they radiate from a'common centre, they are nevertheless separate from and unconnected with each other, and are therefore free to move in any direction within their respective mortises, and can be withdrawn from or adjusted in the, piston case with the greatest facility. They revolve upon a centre pin; 0, rigidly secured to the end of the cylinder opposite that in which the piston drum has its bearing, and extending out into the hollow drum. The pin is encircled by a loose sleeve, 0-, upon which the conveying ends of the pistons rest, and which forms a support for holding them apart and in their proper positions. By means of this pin and sleeve the motion of the pistons is constantly maintained concentric with the outer cylinder, and thus the friction of the pistons against the steam cylinder is almost wholly obviated. The pistons are moreover held in place in the mortises by the pieces cl, whose cross-section is of segmental form. These segmental pieces not only serve to support the pistons, but to also pack them, and prevent any escape of steam into the interior of the drum; for by reason of their rounded shape they easily conform to the least movement of the pistons and piston case, while their flat surface, constantly bearing against the pistons, renders them steam tight. In the edge of the pistons are formed V shaped grooves in which I place the pris matie pieces f. These pieces serve to pack tightly the pistons, and at the same time give them more of a bearing against the cylinder, and present a greater surface to the action of the steam. They are unattached to the pistons, and are held in place-between the two sides of the V-shaped grooves, and the interior surface of the cylinder. They may thus be removed or fitted in position as desired, and can be easily replaced when they become worn by friction or otherwise impaired. In order to prevent the steam from passing by or hearing against the end of the pistons and piston case, I place in the end of the cylinder a disk or plate, I), through which the pin 0 passes. The disk is eircular'andof the diameter of the interiorof cylinder, so that it shall fit over or cover the whole end of the piston. Between the disk and the end of the cylinder are placed' springs k, which serve to hold up the disk against the pistons,-with a yielding pressure, so that it may be able to adjust itself in the movement of the piston-head, or to its conformation. The contiguous'sides of the pistons may he so arranged as to interlock one with the other if desired; this, however, is not necessary, as bythe means already described they are held with sufiieient firmness and accuracy. The arrangement of the valve for regulatingthe admissionof steam into the cylinder is represented in fig. 1. There are three ports,'0,'p, and r, formed in the head of the cylinder, which are covered by the circular plate or valve .9, which is capable of being movedor rotated within a box, s., .The plates has a channel, t, and opening informed in it which have no connection with eachother, and are so arranged that when the opening a is over one of theportsp or r, communication shall be established between the other port and the inlet 0, through the medium offth'e channel '6. By this means steam may be admitted through either of the ports 1; r, and the shaft 11 rotated in either direction If, for instance, the steamjs to be introduced through the port 10, fig. 2, to move in the-direction of the arrow, the valve is turned so as to bring the channel t over the ports 0 and p, the opening a being over .the :port 1'. The steam enters through the induction pipes in port 0, and thence passes through the channel t and port 10, into the cylinder, striking against the pistons and causing the rotation of the drum. A; soon as the steam in the rotation of the pistons reaches the outlet v', it escapes from the cylinder, forces its way up through the opening a, and passing between the valve and its surrounding box, issues frcm'the exhaust E, which is attached to the. cylindcr'so as to open into the space between the valves and its box s. Now, if it be desired to reverse the,- action of the engine, the valve is rotated until the exhaust opening 1) is brought over the port 12, when the two ports a and a will be put in communication, and the steam will enter the cylinder through accusing the piston case to rotatein a contrary direction. The steam cylinder'is' supported by two standards C D, which eonstitute bearings for trunnions placed in opposite sidesof-thecylinder, and by the standards E which alsoz support the shaftof the piston-case. In order not to interfere with the rotation of the shaft at the'poiiit where the standards E are attached, it is surrounded by a sleeve, m, which is seourediwithin a ring, it, by means of bolts 2, and'the latter is connected with the standards E by trunnions or other means. Under this arrangement butthree bearing points are employed in suspending the steam cylinder, viz, two points CD, on opposite sides,of the cylinder, the third point being the bearing of the shaft of the piston case. As the sleeve m 'is loose upon the shaft a, and the trunnions which uphold the cylinder are capable of moving in their boxes in the standards 0, the cylinder is consequently supported in swinging or adjustable bearings, and is enabled to accommodate itself to any resistance which may accidentally arise. Instead of pressing thedisk it against the piston by springs 7c, steam may be introduced between the disk and the end of" the cylinder, thus forming an elastic backing which will hold the disk firmly against the pistons. In case steam be employed, a packing can be arranged in the edge of the disk so as to expand under the action of the steam, and prevent the steam from passing into or out of the cylinder; but,no'rnatter what means are employed for holding up the disk, the latter should always be packed tight s9 as to pr'eventany escape of steam. It will ofcourse be understood that the. central pin a may be used with the pistonsb, either with or without the auxiliary sleeve or tube a.

Having described my invention, and the manner in which the same is or may be carried into etl'ecawhat I claim, and desire to secure by Letters Patent, is-- v 1. The combination, with. the steam cylinder and eccentric-piston case, of the pistons'undcr the arrangement herein described, so that the said pistons, although revolving upon a common axis or centre-of motion, concentric withthat of thesteam cylinder, shall be nnconnected'with and separate from each other and the said cylinder, substantially as shown and described.

2. The combination of the hollow piston case, mounted upon a shaft having its bearing in one end of, and' eccentrically to, the steam cylinder, with the pistons separate from each other, but revolving upon a common axis, which is also the axis of the steam cylinder, substantially as shown and set forth.

3. The arrangement of the steam cylinder with reference to its three bearingpoints, located one upon each side ofthe cylinder, and the third upon the shaft of the piston case, substantially in the manner and for the purposes herein specified. i

In testimony whereof I have signed my name to this specification before two subscribing witnesses.

JOHN P. Briton.

Witnesses:

J. R. Massey, HENRY J. SNYDER. 

